The FARC guerrilla army in Colombia has called off its unilateral cease-fire against the government in the wake of an airstrike by Colombia's military that left 26 people dead.

Twenty-six members of the Revolutionary Armed Forces of Colombia, or FARC in Spanish, were killed Thursday in the airstrike in the western department of Cauca, Colombia's military said in a statement.

President Juan Manuel Santos — who has staked his political reputation on achieving a peace deal with one of the oldest active rebel armies in the world — confirmed the attack on Friday morning from his office in Bogota.

He told reporters that the bloodshed was the "result of clear and forceful action against narco-trafficking, illegal mining, and extortion," all known sources of income for the FARC.

The attack occurred at 2 p.m. a tiny rural settlement near the town of Guapí, in an area considered under rebel control. Military officials said they confiscated 37 weapons and rescued a girl who had been injured in the strike.

The FARC guerrilla army in Colombia has called off its unilateral cease-fire against the government in the wake of an airstrike by Colombia's military that left 26 people dead.

Twenty-six members of the Revolutionary Armed Forces of Colombia, or FARC in Spanish, were killed Thursday in the airstrike in the western department of Cauca, Colombia's military said in a statement.

President Juan Manuel Santos — who has staked his political reputation on achieving a peace deal with one of the oldest active rebel armies in the world — confirmed the attack on Friday morning from his office in Bogota.

He told reporters that the bloodshed was the "result of clear and forceful action against narco-trafficking, illegal mining, and extortion," all known sources of income for the FARC.

The attack occurred at 2 p.m. a tiny rural settlement near the town of Guapí, in an area considered under rebel control. Military officials said they confiscated 37 weapons and rescued a girl who had been injured in the strike.

In a communique announcing the end of their unilateral combat truce, the FARC said it was still hopeful for a permanent end to the conflict. The rebels also renewed their call for a ceasefire observed by both sides.

"We hurt equally for the deaths of guerrillas and soldiers, sons of the same town, from the same poor families. We must stop this bloodshed," the statement said.

A FARC leader known by his alias Pastor Alape described the attack as a "treacherous and degrading act."

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It was not clear how the Thursday strike and the FARC's Friday reversal on disengagement could affect the ongoing peace talks between Colombia and the rebels in Havana, Cuba. Colombia's armed conflict has lasted fifty years and has left hundreds of thousands dead or displaced. Peace talks to end the conflict started in November 2012.

Thursday's attack — coordinated between the Colombian air force, army, and police — marks the first major blow dealt to the rebels since President Santos renewed airstrikes against the rebel group following an ambush that killed 11 army soldiers in the same department last month.

Officials said they were targeting the FARC's 29th Front, which the military blamed for a deadly attack on a police station in November.

In Popayán, the department's capital, a festival encouraging young people to get involved with the peace process is taking place. The mood was festive but some attendees told VICE News that a unilateral ceasefire was basically "meaningless."

Related: Is Peace At Risk After Latest Attack on Soldiers in Colombia?